Inclosed-arc device.



C. V. FERGUSON.

INCLOSED'ARC DEVICE APPLICATION FILED JULY 3|19l6- Inventor: Charles V.Ferguson,

i MHIES V. FERGUSON, OF SCHENECTADY, NEW YORK, ASSIGINOR 'JlO GENERALELEC- A eoaaroe TION 01F Y0 a environ.

application tiled July 3, 1916. Serial No. 107,276.

To all whom it may concern:

Be it known that T, Crmmens V. Fnneoson, a citizen of the United States,residing at Schenectady, in the county of Schenectady, State of NewYork, have invented certain new and useful Improvements .in Inclosed-Arc Devices, of which the following is a specification.

The present invention relates to devices in which an arc is operatedbetween an in-. candescent cathode and an anode operating below'thetemperature of appreciable electron emission, ina' sealed envelop,such, for example, as the incandescent cathode rectifier describedinMeikle Patent No. 1,182,290. In the rectifier described in this patentan arc is operated between a heated tungsten cathode and an anode oftungsten, or other suitable conductive material, in-an atmosphere ofinert gas, such, for example, as nitrogen, argon, or mercury vapor. ][tis stated in the patent that electronegative gases such aswater vapor,oxygen and chlorin must be carefully excluded to avoid deleteriousdisintegration of the cathode.

I have discovered that iodin vapor constitutes a striking exceptionamong electroaid negative gases in an incandescent cathode device. Notonly is the electrical disintegration of the cathode in an arc devicecontaining iodin negligible, but iodin on the other hand possessesdistinctive properties advantageous to the operation of an arcparticularly in a rectifier. One of the main advantages of iodin vaporin a rectifier is the substantial inhibition of arcing from an electrodenot intended to act as cathode,

for example, from anode to cathode, or between two anodes. The voltagedrop of an arc in iodin vapor is relatively low and substantiallyinvariable. The accompanying drawing shows one specific form of hotcathode device embodying my invention. T wish it to be understood thatthis is shown for illustrative purposes only as my invention is ofgeneral application. The particular cathode structure shown is describedand claimed in another copending application.

Referring to the drawing, the device shown comprises a cathode 1,consisting of tungsten, or other suitable refractory material, and ananode 2, which also consists of tungsten, molybdenum, copper or othersuitable conductive material. An anode conductor 3, and cathodeconductors 4, 5, are sealed into the envelop 6 in the usual manner. Thestructural features of the electrodes are not part of thepresentinvention.

When the envelop has been evacuated in the usual manner, water vaporbeing carefully removed, some ure iodin is introduced, for example, trough a side tube afterward sealed ofl' and not shown in the drawing.The quantity of iodin should be suflicient and the operating temperatureof the bulb high enough to create a pressure of iodin vapor equal to atleast about one-half millimeter of mercury. The best rectificationappears to be obtained at pressures up to about millimeters.

The drop of voltage in an arc of about five amperes in iodin vapor isabout 23 volts. The tendency for arcing to occur from anode to cathodeupon the reversal of polarity is so low that alternating currents ofhigh voltage, for example, 700 to 800 volts, may be readily rectified iniodin vapor..

What T'claim as new and desire to secure by Letters Patent of the UnitedStates, is

ate at incandescence, a cooperating anode and a quantity of iodin, aninclosing container, said container operating at a temperature at whichthe iodin has a vapor pressure exceeding about one-half millimeter ofmercury.

3. The method of suppressing deleterious arcing from anode to cathode inan are de-.

vice provided with a cathode operating at incandescence and an anodeoperating below the temperature at which electronem ss on is,appreciable, which consists in providing an environment of iodinvaporfor the arc during the operation of. the device.

In witness whereof, T have hereunto set my hand this 30th day of June,1916.

, cLEs v. rnnensou.

